Updated 9:11 a.m.| In its first endorsement of a House challenger in the 2018 cycle, EMILY’s List is backing Katie Porter, a law professor challenging California Republican Rep. Mimi Walters. The early endorsement signals that the abortion rights group will be aggressively targeting House Republicans in the midterm elections.

“EMILY’s List is thrilled to endorse Katie Porter in this critical race to take back the House of Representatives,” Stephanie Schriock, the president of EMILY’s List, said in a statement. “We need leaders on Capitol Hill who aren’t afraid to stand up to [Donald] Trump associates, big banks, and entrenched special interests who wield tremendous power over the White House, the Trump family, and a Republican-controlled Congress.”

EMILY’s List supports Democratic female candidates who support abortion rights. With the endorsement, Porter will have access to potential donors in the group’s five-million-strong membership. The timing of the endorsement allows for a month of fundraising before the current fundraising quarter ends on June 30.

The group is also actively recruiting women to run in similar districts across the country, and is experiencing an unprecedented interest from potential candidates, having already heard from 14,000 interested women from the federal to local levels, a spokesperson said. That’s compared to around 900 interested candidates in the entire 2016 election cycle.

Harris tapped Porter to oversee distribution of a major mortgage settlement when Harris was the state’s attorney general. Warren taught Porter at Harvard Law School, and co-authored a chapter in Porter’s book on debt.

“We can and will take back the House of Representatives — starting by flipping seats from Republicans like Mimi Walters who allow abuses of power to go unchecked,” Warren said in a statement on the EMILY’s List announcement.

Walters’ Orange County-based 45th District is historically more conservative. Nearly 40 percent of the registered voters are Republicans, while roughly 30 percent are Democrats. Republican presidential nominee Mitt Romney carried the district by 12 points in 2012. But Democrat Hillary Clinton took it by 5 points over President Donald Trump last fall, according to calculations by Daily Kos Elections, and making the district a Democratic target in 2018.

In addition to Porter, other Democratic challengers taking on Walters include David Min, also a UC Irvine professor and a former staffer for Senate Minority Leader Charles E. Schumer, and Kia Hamadanchy, a former staffer for Ohio Democratic Sen. Sherrod Brown and the son of Iranian immigrants.

Under California law, all candidates run in an open primary with the top two vote-getters, regardless of party, advancing to the general election.

Clarifies that while EMILY's List has backed incumbents already this cycle, this is the first House challenger the group has endorsed.Get breaking news alerts and more from Roll Call on your iPhone or your Android.